Help! What would you do next? Hemi misfire and low power

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horbizzle

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2009 1500 hemi 5.7 with 265,000 mi on it.

Yes I have the hemi tick. Yes I have a bit of an exhaust leak. Had those for years with the engine running fantastic. Those are not the problems right now.

Last week the truck started lacking in power. Then when it was cold, about two blocks from home it would go into limp mode and start throwing codes. P0300 random misfire code. And then p0303 for cylinder 3.

The thing is, if I pulled over to the side of the road and shut down and restarted two or three times, everything would act normal again and I wouldn't throw any more codes. The truck would run, although a little underpowered and sluggish. But the codes would not return for the rest of the day.

So I changed all the plugs and put on brand new coil packs.

Fired it up and it idle smoothly. Took it out for a drive and it seemed to be fine until I got above 3K RPM and then it started throwing a p0300 code again. This time it threw a p0305 code as well. Now cylinder 5 seemed to have a problem. But no P0303 code anymore.

Same thing though. Pulled over, shut it off and restarted it several times and it went away. Drove perfectly fine the rest of the day. No more codes. Yet still sluggish though.

Today I started the truck and for the first 15 minutes of driving I never let it give above 2K RPM. Drove it all day with no code. No check engine light. No warnings. Still underpowered though.

Even when it is running good, it does start hard and ping a little when you first fire it up. I also noticed that I am hearing a strange whistling coming from the engine on acceleration. It is a pulsing whistle that mirrors the RPMs. I thought it was an air leak and I checked everything but it all is tight. Air box, throttle body, etc.

Could this be an issue with my injectors?

Could it be my PCM?

God forbid, but could it be my cam? (I wouldn't think that because the truck runs decently once the engine stops throwing codes)

What would you do next?
 

Burla

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How sure are you about the 3 and the 5, because you happen to have the codes that are very similar in appearance on the obd. Cam would be the most likely culprit if it was one or the other, despite what you are saying. Cam's usually fail like that in stages before massive fail. Especially known for starting ok, when you have this mis fire code is it there at start up or after a while?

No other codes? Have someone gas it in park and isolate that whistling, maybe vacuum leak which would be great, but I wouldn't say likely.

If your sure it is 3 and 5, then most likely not the cam.
 
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horbizzle

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I’m 100% sure of the codes. It throws a constant P0300 when it’s acting up. But the few times it threw an actual code was a P0303 before changing plugs and coil packs, and then a P0305 after. But today I can’t seem to get anything other than a P0300.

However, this is the weird part, and why I don’t think it’s the cam.

Just about an hour ago I took the truck to the store that is 2 miles away. I kept it under 2k rpm for most of the way there. It ran fine until about a block from the store when it began to misfire, stutter, whistle, and throw a code. It ended up being a P0300.

I shut it down and went in the store. When I came out about 10 minutes later, the truck started roughly and you could tell it had a dead cylinder misfire. Still just a P0300 though. I brought the RPMs up to about 2500 and held it there for a minute. Then I shut the truck off, cleared the code, restarted it and it ran smoothly again without the misfire. I drove it the 2 miles back home without any further code or misfire. I even got on the throttle a little and it rev’d solid to around 4k under hard acceleration. However, you could tell there was some hesitation and sluggishness, and could hear some pinging when it shifted from 1st to 2nd. But it didn’t throw a code or misfire.

Could this be vacuum? Where would I even start looking for that?

Could this possibly be a bad sensor like a cam position or a crank sensor? I’m thinking of just changing those out tomorrow to rule them out.

Things are tight right now so I can’t afford to take it to a dealership or mechanic, and definitely can’t replace the truck or engine… I just dropped like $300 for the plugs and packs which I’m thinking I may not have even needed now because they all looked ok and evenly toasted. I have relatively solid mechanic experience so I have to figure out what the heck is happening on my own if I can.
 

Burla

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It will help if you have someone on the pedal and find the whistle, my guess throttle body area. Most surely this can cause misfire. Could try and drive with no air filter don't go through dust storm, just for further diagnose if you cant find it
 

Burla

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For sh!ts and giggle check the intake manifold bolts,i doubt they're your issue,but give them a check anyways.There's 10 of them,and they call for 108 in-lbs not ft-lbs.
with so many miles, the pcv probably needed to be replaced two or three times by now. If that wasn't replaced, do you think it could pop that intake mani? Probably so hey, good call.
 
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horbizzle

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I'll add a PVC to the list! Might just change ALL the sensors while I'm at it. Probably some of them bad or about to go bad after 265k miles.

I ran it without an intake after I did the plugs and coils and it didn't change anything. I'll have to see if I can get the gf to man the throttle while I check around for leaks.

The more I think about it, the whistling didn't start until after I put the new plugs and coils in, which makes me think that I might have knocked something loose. Maybe at the back of the intake when I was trying to get to the back plugs?

But here's the thing... the misfires, P0300/P0303 codes, and rough running is what got me to change the plugs/coils to begin with. So the whistling is something new.

I will check the intake bolts as well as the throttle body as well.
 

crash68

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Check the fuel pressure, be sure to rev the engine up over 3K-4K to see if the pressure drops off. Also try moving the #3 and #5 fuel injectors to different cylinders
 
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horbizzle

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Ok, I'm really curious as to how you did this?
Hahaha. Sorry. I meant without the airbox and intake tube connected to the throttle body. Just to see if there was anything clogging the airflow.

Also without the air cleaner as well. I do have a new backup air filter but the one I had in there wasn’t very old.
 

Dusty

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I’m 100% sure of the codes. It throws a constant P0300 when it’s acting up. But the few times it threw an actual code was a P0303 before changing plugs and coil packs, and then a P0305 after. But today I can’t seem to get anything other than a P0300.

However, this is the weird part, and why I don’t think it’s the cam.

Just about an hour ago I took the truck to the store that is 2 miles away. I kept it under 2k rpm for most of the way there. It ran fine until about a block from the store when it began to misfire, stutter, whistle, and throw a code. It ended up being a P0300.

I shut it down and went in the store. When I came out about 10 minutes later, the truck started roughly and you could tell it had a dead cylinder misfire. Still just a P0300 though. I brought the RPMs up to about 2500 and held it there for a minute. Then I shut the truck off, cleared the code, restarted it and it ran smoothly again without the misfire. I drove it the 2 miles back home without any further code or misfire. I even got on the throttle a little and it rev’d solid to around 4k under hard acceleration. However, you could tell there was some hesitation and sluggishness, and could hear some pinging when it shifted from 1st to 2nd. But it didn’t throw a code or misfire.

Could this be vacuum? Where would I even start looking for that?

Could this possibly be a bad sensor like a cam position or a crank sensor? I’m thinking of just changing those out tomorrow to rule them out.

Things are tight right now so I can’t afford to take it to a dealership or mechanic, and definitely can’t replace the truck or engine… I just dropped like $300 for the plugs and packs which I’m thinking I may not have even needed now because they all looked ok and evenly toasted. I have relatively solid mechanic experience so I have to figure out what the heck is happening on my own if I can.
It sounds like you're shotgunning.

If you are installing new parts en mass, especially aftermarket parts, you could be injecting new problems into the issue. I would've swapped coils between a non-code cylinder and tested the engine first. I would suggest getting a scan while the engine is running. You could have a cam timing issue or even an O2 sensor failing (fuel trim check). The price of a scanner diagnosis might end up being cheaper that a basket full of parts.

My son recently resolved a P0300 issue on his 2500 with the 6.4 by replacing the PCV valve.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 110743 miles.
 
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horbizzle

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So... A whole new bunch of info.

Truck ran sluggish but no codes for a 10 mile round trip this morning. But then later in the afternoon I tried to go 2 miles to the store and it died in the street when I came to a stop at a light.

Codes galore!

Standard P0300

But now...
P0306 (Cylinder 6 misfire)
P0608 (Control module VSS output "A")

P1411
P1414
P1416 (Secondary Air Injection System Bank 2)
P1417
(All related to MDS I believe)

P0420 (O2 Sensor, but not specified which one)
P0273 (Cylinder 5 Injector Circuit Low)
P2450 (Evaporative Emissions Control Systems switching valve performance or stuck open)
P1524 (Throttle Closed Position Performance)

The whistle is more like a "harmonic flutter" and has gotten louder and more constant with the throttle. It's very loud on startup and then gets louder as you accelerate or just pop the throttle.

When it's actually running it's sluggish as hell and feels like I'm pulling a trailer. It pings on each shift when the rps drop and it's under load.

Oh...the slight exhaust leak I had on the passenger side has suddenly become louder as well, and there's a new exhaust smell in the cab. Awesome!

Where do I even start with all this?

Or do I just throw 30lbs of tannerite under it and hit it with my 6.5 creedmore from a few hundred yards away?
 

Burla

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Whenever you see a ton of codes not related first suspect is battery and/or alternator. how old is battery? Could be bad ground as well, bad connection wire clean those terminals.
 

Wulf

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Whenever you see a ton of codes not related first suspect is battery and/or alternator. how old is battery? Could be bad ground as well, bad connection wire clean those terminals.
The more complicated the vehicles get, the more finicky they can be about 'clean' voltage. This ^ sounds like a solid idea, and a cheap fix if it solves some of the problems.

My other vehicle (2012 Chevy 1500) has developed an exhaust leak as well, but it has >97k on the clock, so that is something that could happen. The harmonic flutter, since you said it seems to be tied to the throttle, could be a part of the exhaust leak you think you have.
 
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horbizzle

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You know thats a good point! The battery is going on 4 years old now, and about a month ago I accidentally ran it dead while in the driveway. I boosted it to start and even threw a charger on it overnight, but I have noticed a little bit of a lag and sluggish starting. Plus I live in North Dakota and those batteries definitely have their work cut out for them in the winter.

I may start there and go get a new one today.

As for the exhaust leak... It's had it for awhile now, just has gotten louder through all this. It seems weird that immediatly after replacing the plugs and coils that it would get louder like that. I had the typical Hemi sheared manifold bolts happen awhile back and had new manifolds installed professionally roughly 3 years ago. I suspect that they have either broken again or come lose. I'll jack it up and take the wheel and wheelwell off if I can later today and see if I can get to them.

I'll swap the battery, reset the pcm, clear the codes, and report back what I find.

Thank you for your suggestions!
 

Burla

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You know thats a good point! The battery is going on 4 years old now, and about a month ago I accidentally ran it dead while in the driveway. I boosted it to start and even threw a charger on it overnight, but I have noticed a little bit of a lag and sluggish starting. Plus I live in North Dakota and those batteries definitely have their work cut out for them in the winter.

I may start there and go get a new one today.

As for the exhaust leak... It's had it for awhile now, just has gotten louder through all this. It seems weird that immediatly after replacing the plugs and coils that it would get louder like that. I had the typical Hemi sheared manifold bolts happen awhile back and had new manifolds installed professionally roughly 3 years ago. I suspect that they have either broken again or come lose. I'll jack it up and take the wheel and wheelwell off if I can later today and see if I can get to them.

I'll swap the battery, reset the pcm, clear the codes, and report back what I find.

Thank you for your suggestions!
cold is good for battery life, but bad for capacity, and hemi's of course need capacity and a lot of cca. Some guys in the cold go to h8 and make them fit, the theory is a little extra capacity will let you take advantage of the cold preserving that battery.

ity-battery-life-compared-at-different-temperature.jpg
 
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